Various floating support structures intended for installing offshore multi-megawatt wind turbines are currently under development in many countries. Depending on the depth of the site considered, several design options are possible. Despite their great diversity, several floating support families emerge, among which:                SPAR type floaters, characterized by a slender geometric shape and comprising significant ballast so as to lower the center of gravity of the whole structure to the maximum and thus to provide stability,        barge type floaters are very wide shallow drafted support structures. Their stability is provided by their wide waterplane area. However, this type of support structure is very sensitive to wave motion,        TLP (Tension Leg Platform) type support structures that have the specific feature of being moored to the seabed by taut cables providing structure stability, and        semi-submersible type floaters are support structures consisting of at least three floaters connected by arms providing stiffness. These support structures generally have a low displacement and a great waterplane area inertia, thus providing sufficient righting moment for the stability thereof. Furthermore, this type of floater is less sensitive to wave motion than barges.        
Floating support structures can also be used in other fields than offshore wind turbine installation, for example for hydrocarbon production means, wave energy conversion systems (for converting wave energy to mechanical or electrical energy), etc.
In order to enable damping of the motion caused by the waves, various damping solutions have been considered for these floaters.
According to a first solution, damping can be achieved using a ballast system with a “U tube” comprising a liquid that can move between the two vertical branches of the U. This solution is notably described in the following document:                C. Coudurier, O. Lepreux and N. Petit, Passive and semi-active control of an offshore floating wind turbine using a tuned liquid column damper, in Proc. of 10th IFAC Conference on Manoeuvring and Control of Marine Craft, MCMC, 2015.        
However, this solution only allows to damp the motion caused by the waves in a single direction. Indeed, for waves whose direction is not parallel to the “U tube”, the motion is not damped. Now, at sea, the direction of the wave motion is variable with time, therefore the motion is not constantly parallel to the “U tube”.
Besides, the stability problem also arises in other fields, for example for bottom-fixed structures (notably bottom-fixed wind turbines) that are subjected to stresses caused by the wave motion, as well as civil engineering structures (buildings, bridges) that may undergo stresses caused by the wind or by an earthquake.
The present invention thus relates to a stabilization system for a system subjected to external stresses, the stabilization system comprising at least three liquid reserves and at least three connecting tubes. The liquid reserves are spatially distributed (not located in one plane). Furthermore, the connecting tubes provide circulation of the liquid between all the liquid reserves. The liquid can thus flow in all directions in order to damp excitations, whatever the direction of the wave motion.